Capturing the motion and emotion of the Leslie speaker cabinet.
Just as Helen of Troy's beauty launched a thousand ships, the sound of the Leslie "tone" cabinet has launched a thousand emulations. But even the best of them - and there are some good ones - pale in comparison to the real thing. What makes the Leslie sound so compelling? In a word, motion. The sound from a Leslie cabinet moves not only outward but also in a circular direction around a pivot - sort of like the sparks from a fireworks pinwheel. As the sound spins out at varying speeds from the Leslie's rotating components, the listener hears a complex blend of Doppler effects (including frequency and amplitude modulation), phase shifting, frequency masking, and ambient reverberation. That highly animated sound is further colored by the Leslie's tube-driven amplifier, which often is driven to distortion.
It's no wonder most musicians and producers prefer recording the real thing to using an emulation. But is it really possible to accurately capture the magical sonic phenomenon you encounter in a nightclub while listening to the likes of a Jimmy Smith, Joey DeFrancesco, or Larry Goldings (to name just a few masters of the classic Hammond B-3/Leslie combination)? No, not really. No matter how well you record a Leslie, the experience of being in the room with the Earl of Whirl is simply not going to translate fully through a pair of stationary speakers. But take heart: many of the elements that make up the Leslie sound can be documented faithfully in the recording studio.
BRICK HOUSEOf the many Leslie models that were built, the most popular are the 145, 147, and 122, which I will focus on. Those models share several features, including a three-compartment cabinet design. The top compartment houses a rotating treble horn with identical-looking bells that face opposite directions from each other. Note that only one of the bells channels sound; the other is a dummy that acts as a counterbalance so the assembly spins smoothly without wobbling. Also worth noting is that the horn assembly is mounted off-center in the cabinet - an important detail in some miking setups.
The cabinet's closed middle compartment contains the high- and low-frequency drivers and 800 Hz passive crossover. The treble unit is a 3/4-inch Jensen compression driver (the kind used in P.A. speakers) connected to a vertical tube that feeds into the rotating horn assembly. Bass frequencies are handled by a 15-inch speaker that fires downward into a rotating wooden drum located in the cabinet's lower compartment (see Fig. 1). The lower compartment also houses the Leslie's 40-watt monophonic tube amplifier.
The treble horn and wooden drum are turned by rotors driven by two dual-speed motors, letting the player choose between slow and fast rotation speeds - for chorus and tremolo, respectively - independently for each element. Interestingly, the wooden drum turns clockwise and the treble horn counterclockwise. In addition, the two units' rotation speeds, though roughly the same at slow and fast settings, differ during ramp-up and ramp-down times because of the wooden drum's greater mass - yet another factor that can deepen the complexity of the sonic stew.
These and other construction details can be critical to the recording engineer because Leslie owners tend to modify their cabinets in various ways. Organ players who kick bass, for example, often don't want chorus or tremolo on the low notes, so they might disable the motor that turns the wooden drum. Other players, for whatever reason, sometimes disable the top motor. Obviously, in either case, the recording engineer who is unaware of the modification is at a disadvantage. If the top motor is disabled, for example, the engineer needs to manually align the sound-producing horn with the mic.
Other Leslie mods include mechanically linking the top and bottom rotors so that they turn at the same speed (this gives a more dramatic Leslie sound); switching out the power amp for a more powerful one or disabling it and using an external combo preamp; using different treble and bass drivers (typically because the stock ones were blown); installing a different crossover; or even bi-amping the treble and bass drivers. Although none of these modifications should influence the recording as much as disabling a motor, any will alter the sound and therefore may also affect how you record the Leslie.
You may encounter numerous other original Leslie models, including the older models 45, 47, and 22 (which are identical to the 145, 147, and 122 except that they have single-speed rather than dual-speed rotors). Other original Leslie models, such as the 51, do not contain amplifiers and must therefore be connected to an external amp. In addition, since CBS bought the Leslie company in 1965, several new models have been produced, including the 122A, 122XB, and 147A, as well as larger models made for multichannel organs. It is important when recording new or unusual Leslies to survey the construction carefully in case the unit employs a design change (a side-firing woofer, for example) that would affect sound production.
TIGHT SHIPLike a neglected drum set that squeaks and rattles each time it is struck, a rickety old Leslie can be a Pandora's box of extraneous noise. Therefore, in addition to checking for any modifications, another important step is to listen carefully to the cabinet while the musician plays at full recording volume. (If the instrument is an organ, make sure the player uses the same drawbar settings that will be used during recording.) If you hear creaking, buzzing, or other unwanted noise - I specify "unwanted" because some of the resonances and distortions produced by a Leslie cabinet may be desirable - have the musician play chromatic scales slowly from lowest note to highest so you can pinpoint the note or notes that set off the noise. If you don't hear the offending sound on single notes, try chords.
After determining which note or group of notes cause the noise, locate where the unwanted sound is coming from. The last Leslie I recorded had an obnoxious sympathetic buzz that I traced to some loose wood plies on the bottom-most panel. After discovering that I could stop the buzz with my hand, I put a piece of foam rubber on the spot and weighted it down with a 10-pound dumbbell. That didn't completely stop the buzz, but it did damp it sufficiently for the recording.
Other common sources of noise are the Leslie's motors, rotors, belts, and pulleys - any parts that move, basically. Hopefully, the player maintained those mechanical parts well. If not, you need to track down the noises and squelch them or move the microphones back from the source to minimize pickup of the unwanted sound.
FREE REIGNIn addition to its historical role as bedfellow to the B-3 and C-3 organs, the Leslie cabinet also gets coupled with other instruments such as guitar, vocals, harmonica, other organs and keyboards, or anything that strikes the player's or producer's fancy. Likewise, there are 101 ways to record a Leslie, depending on the application and your creative bent. Variables include the usual suspects: number of mics (and tracks), mic selection, mic placement, and ambient sound.
As for mic selection, Leslies don't put out much high-frequency content above 12 kHz, so you can obtain good results with almost any decent microphone, whether dynamic or condenser. Indeed, many classic B-3/Leslie tracks have been recorded using just a couple of Shure SM 57s up top with perhaps a Sennheiser MD 421 positioned at the bottom of the cabinet to capture the low end.
Some positioning issues come up no matter how many mics you use. A primary question is whether to aim the mic(s) directly at the source(s) through the Leslie cabinet's open back (with the upper and lower panels removed) or through the louvers on the cabinet's front or sides. Miking from the open back gives a slightly brighter, more open sound but is prone to capturing more extraneous noise, including wind from the spinning horn or drum and mechanical noise from the rotors. For that reason pop filters or foam windscreens may be advisable when miking from the back, especially when using condenser mics. Miking through the louvers provides a mellower sound and cuts down significantly on wind noise from the rotating elements. As usual, the best approach is to try several miking arrangements, compare the results, and choose the setup that sounds best for the song.
ONE FOR THE MONEYFor a dense mix with scads of instruments, a mono Leslie track may be sufficient. Fortunately, Leslies usually sound so great that even a strategically placed single mic can capture a killer sound.
The trick here is to record in a great-sounding, reverberant room with the mic positioned far enough away from the cabinet to capture a natural sound. Simply move around the space and use your ears to determine where to put the mic while bearing in mind that you are listening for a blend of ambient and direct sound. A small tiled bathroom makes an excellent Leslie chamber, especially for capturing a huge sound on a single track. In that case, I would probably use a large-diaphragm condenser set to the omnidirectional polar pattern or a single-point omni such as the Earthworks QTC1.
TWO FOR THE THROWThere are two approaches to miking a Leslie with two mics: put one mic on top to capture the treble and a second one on the bottom to record the bass, or use a matching pair positioned to capture a stereo image of the rotating treble horn. Obviously, the first is the better option if you have a B-3 player kicking bass (assuming no other bass instrument is in the mix). In that case, a mic with a good low-end response - for example, a ribbon microphone or a large-diaphragm mic - is the best choice for the bottom. Try panning the bass track dead center and the treble track to one side or the other, say, at ten or two o'clock.
A number of setups will work for the matched mic pair on the rotating treble horn. If miking through the louvers, try positioning the mics on two sides of the cabinet, at either a 90- or a 180-degree angle to each other (see Figs. 2a and 2b) and at an equal distance from the cabinet (typically four to eight inches away). For stereo miking from the back of the cabinet (with the top panel removed, of course), position the mics at a 90-degree angle to each other with both aimed at the treble-horn assembly (see Figs. 2c and 3). Remember to take into account the off-center mounting of the horns.
Panning the tracks hard left and right will create the fullest sound and greatest sense of movement between the stereo mic signals. However, such extreme panning may sound unnatural, especially if you try to create a soundstage with a discernible location for each instrument. Pan the two tracks closer together for a more natural sound.
THREE'S COMPANYAlthough two is the minimum number of microphones required to capture some "motion" from a Leslie, at least three mics are required to capture both treble-horn motion and the unit's full frequency range. When using three microphones, position the matched pair as described earlier and train the third mic on the rotating wooden drum that channels sound from the 15-inch woofer (see Fig. 4). That drum can put out a fair amount of wind, especially when spinning at full speed, so if miking from the back of the cabinet, you may need to employ a pop filter or windscreen. (Note that newer Leslies use a Styrofoam drum, which is lighter and produces less wind than the wooden drums.) If the player disabled the lower motor, a pop filter won't be necessary; however, make sure to turn the drum so that the port is facing the mic.
Again, for the fullest sound and most motion, pan the stereo tracks hard left and right and put the bass track dead center. To locate the organ (or whatever) on a more believable soundstage, group the three tracks closer together - only two or three "hours" apart - again with the bass track in the center and the stereo tracks on either side.
FAB FOUR, FAB FIVETo create the greatest sense of motion, add a second bass mic - preferably the same model as the first - and record onto four tracks. As with the stereo pair up top, position the two lower mics at a 90- or 180-degree angle to each other. (The configuration of the bass mics to the treble mics - whether on the same, opposite, or adjacent sides of the Leslie - is not critical, but you may want to experiment just the same to find the combination you like best for the song you're recording.)
Afterward, play with the panning to get the desired movement. You could pan each stereo pair hard left and right, of course, but you might also try panning the bass tracks inside the hard-panned treble tracks, perhaps at ten and two o'clock. Or try panning them the other way around, with the bass tracks hard left and right and the treble tracks inside. Still another approach would be to overlap the tracks, with the treble pair panned hard right and ten o'clock and the bass pair panned hard left and two o'clock, for example.
For the most versatile and potentially realistic sound, add a room mic to the mix for a total of five microphones. That mic - a tube condenser would be a nice pick - should be positioned several feet from the Leslie, if not on the other side of the room. Heck, if you want to go all out - say, if you're recording a solo B-3 record - add an XY condenser pair to capture the ambient sound in stereo for a total of six mics and six tracks. If you think that sounds like a lot of mics to keep track of, think of the options you'll face when a B-3 player carts in two Leslies - the way a Hammond was meant to be played, according to the connoisseurs.
SPIN CYCLEAs you can see, there are any number of ways to record and mix a Leslie. This article is hardly exhaustive, but it has outlined some basic tried-and-true techniques and hopefully also provided some helpful tips for engineers new to recording the wondrous Leslie speaker cabinet.